On the tomb of the nineteenth century Church historian Bishop Mandel Creighton are inscribed the words: ‘He tried to write true history.’

Like the bishop – who was a member of my own college at Oxford – I believe that there is such a thing as ‘true history’.

What happened in the past is unalterable and definite. To uncover it – or as much of it as possible – the historian has several tools, among them chronology, documentation, memoirs, and the vast apparatus of scholarly work in which others have delved and laboured in the same vineyard.